c#泛型TryParse類型轉換

標籤：wro   creat   val   reflect   pre   odi   public   div   value   

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Reflection;using System.Data;namespace ConsoleApplication11{    class Program    {        static void Main(string[] args)        {            var dt = new DataTable();            dt.Columns.Add("c1", typeof(string));            var row = dt.NewRow();            row["c1"] = "abc";            var c = getDataFromDBField<double>(row["c1"], 2);   //返回2            var d = getDataFromDBField<object>(row["c1"], 2);   //返回"abc"        }        private static T getDataFromDBField<T>(object obj, T defaultValue = default(T))        {            if (obj == null || obj == DBNull.Value)                return defaultValue;            Type t = typeof(T);            var tryParse = t.GetMethod("TryParse", BindingFlags.Public | BindingFlags.Static, Type.DefaultBinder                , new Type[] { obj.GetType() , t.MakeByRefType() }                , new ParameterModifier[] { new ParameterModifier(2) });            if (tryParse != null)            {                var parameters = new object[] { obj, Activator.CreateInstance(t) };                bool success = (bool)tryParse.Invoke(null, parameters);                if (success)                    return (T)parameters[1];                else                    return defaultValue;            }            return (T)Convert.ChangeType(obj, typeof(T));        }    }}

 

c#泛型TryParse類型轉換